Deep into last Wednesday’s Democratic debate, exasperated Republican strategist John Weaver tweeted: “When the topic is criminal justice, how are they not talking about the criminal in the White House? Huh?”

Weaver, who detests President Donald Trump, nailed it. The Democrats, in their predictable and often desperate zeal to attack one another with gusto, failed to train any substantive firepower on the incumbent – who has presided over a crime scene.

Mired as they were in squabbling among themselves – wading deep into the weeds, yet again, on the abstruse details of health care policy – Donald Trump got off easy. And much as Trump hates CNN, he should send the network a bouquet of flowers, thanking its moderators for goading the Democrats to beat each other up and leave him alone.

Perhaps some TV viewers were galvanized by the intramural attacks on Sen. Kamala Harris’ old tenure as California attorney general (she says she’s proud of it), and by the attacks on Joe Biden’s old senate record (he says he’s proud of it), and by the attacks on Barack Obama – and, by extension, Biden – for deporting millions of undocumented immigrants (some candidates seemed far more upset about Obama than about Trump). But I doubt it.

“No Democrat wants to watch our candidates savaging one another. It’s a gift to the GOP,” said Simon Rosenberg, a center-left Democratic operative.

Here’s an example of a timely topic of national importance that never came up during either night: Trump has forced Dan Coats, the director of national intelligence, to quit his job. Coats, you may recall, was fiercely independent in his assessments of threats to our national security, including Russia and its meddling in the 2016 election.

Trump’s ongoing mission is to subsume the intelligence community, to make it a partisan instrument of his will at the expense of our national security. Which explains why he’s now trying to replace Coats with a congressional toady who has limited intelligence experience, and whose longest stint in public life was eight years as mayor of a small Texas town.

This dire development, which fits into the larger narrative about Trump’s authoritarian instincts at home and weakness abroad, was certainly worthy of attention. The CNN moderators could have asked the candidates about it, or, at risk of breaking the moderators’ “rules,” candidates could have found ways to bring it up.

On the domestic front, here’s something else that never came up: A scant 10 miles from Detroit’s debate auditorium, in the swing county of Macomb, autoworkers are losing their jobs because a historic General Motors plant is shutting down.

Back when Trump campaigned for president in Michigan, he declared: “If I’m elected, you won’t lose one plant, you’ll have plants coming into this country, you’re going to have jobs again, you won’t lose one plant, I promise you that.” The other day, a Trump voter in that community lamented: “He said the jobs would stay here. But then I hear about the plant closing. What the hell is going on?”

Over a span of two nights, not one of the 20 Democratic candidates mentioned this plant closing – and the chasm between Trump’s promise and performance. That might have helped their cause, since wresting Michigan from Trump is a top priority in the next Electoral College tally.

If the CNN moderators had found the time to mention the plant closing (instead of asking Harris to fight anew with Biden over busing that took place 40 years ago), they could’ve teed up a question that the electorate truly cares about: How do these Democrats propose to expand the economy and create good jobs at good wages – in contrast to Trump’s trickle-down economics and fealty to the rich?

Barely a sentence was devoted to that fundamental issue. By contrast, Twitter blew up after Biden greeted Harris on stage by saying, “Go easy on me, kid.” Was “kid” an insult? Was it condescending? Was it just Joe being Joe? Was it a big deal about nothing? Was it a disaster?

Meanwhile, Trump says and does worse whenever he breathes. Thanks to the Democrats’ dearth of perspective, and CNN’s myopic lust for intramural conflict, Trump basically won the debate.

We’re left to wonder whether round three, in September, will yield a better result.

Opinion contributor Dick Polman is the national political columnist at WHYY in Philadelphia and a “Writer in Residence” at the University of Pennsylvania. His work appears on Mondays on the Capital-Star’s Commentary Page. Readers may email him at [email protected].